de.codecentric.boot.admin.journal.web.JournalController.java Source code

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Here is the source code for de.codecentric.boot.admin.journal.web.JournalController.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.codecentric.boot.admin.journal.web;

import static java.util.Collections.synchronizedCollection;

import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedList;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.event.EventListener;
import org.springframework.http.MediaType;
import org.springframework.util.MimeTypeUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

import de.codecentric.boot.admin.event.ClientApplicationEvent;
import de.codecentric.boot.admin.journal.ApplicationEventJournal;

/**
 * REST-Controller for querying all client application events.
 *
 * @author Johannes Edmeier
 */
@ResponseBody
public class JournalController {
    private static Logger LOGGER = LoggerFactory.getLogger(JournalController.class);

    private ApplicationEventJournal eventJournal;
    private final Collection<SseEmitter> emitters = synchronizedCollection(new LinkedList<SseEmitter>());

    public JournalController(ApplicationEventJournal eventJournal) {
        this.eventJournal = eventJournal;
    }

    @RequestMapping(path = "/api/journal", produces = MimeTypeUtils.APPLICATION_JSON_VALUE)
    public Collection<ClientApplicationEvent> getJournal() {
        return eventJournal.getEvents();
    }

    @RequestMapping(path = "/api/journal", produces = "text/event-stream")
    public SseEmitter getJournalEvents() {
        final SseEmitter emitter = new SseEmitter();
        emitter.onCompletion(new Runnable() {
            @Override
            public void run() {
                emitters.remove(emitter);
            }
        });
        emitters.add(emitter);
        return emitter;
    }

    @EventListener
    public void onClientApplicationEvent(ClientApplicationEvent event) {
        for (SseEmitter emitter : new ArrayList<>(emitters)) {
            try {
                emitter.send(event, MediaType.APPLICATION_JSON);
            } catch (Exception ex) {
                LOGGER.debug("Error sending event to client ", ex);
            }
        }
    }
}